WASHINGTON — House Majority Leader Tom DeLay, R-Texas, stepped up his attack on federal judges yesterday, telling a gathering of religious conservatives that the judiciary has “run amok” and demanding that Congress assert authority over the courts.

His remarks, delivered by videotape, broadened the criticism he voiced last week after the death of Terri Schiavo, a severely brain-damaged woman in Florida, after judges refused to order her feeding tube reinserted.

DeLay’s address came as he strives to shore up his base amid a storm over his ethics. Liberal groups have launched ads attacking his connections to lobbyists and former associates now under investigation. News reports have raised questions about his use of campaign cash, and the House ethics committee rebuked him three times in one week last year.

Many lawmakers think DeLay can weather the storm as long as he’s perceived as a leader of the conservative movement.

“The judiciary branch of our government has overstepped its authority on countless occasions, overturning and in some cases just ignoring the legitimate will of the people,” DeLay said. “But I also believe the executive and legislative branches have neglected the proper checks and balances on this behavior. … Our next step, whatever it is, must be more than rhetoric.”

Criticism of the courts by religious conservatives has mounted since the Schiavo case. At issue is legislation that Congress passed and President Bush signed late last month that ordered federal courts to review the case, in which Schiavo’s husband and parents disputed what her wishes would be. A federal judge in Florida refused to overturn a state court’s decision, and the 11th U.S. Circuit Court of Appeals upheld his ruling. The Supreme Court declined to hear an appeal.

After Schiavo died last week, DeLay said federal judges “thumbed their nose at Congress and the president. The time will come for the men responsible for this to answer for their behavior.”

Congress could inject itself into the judiciary by simply calling on judges to testify before Congress, a move that could be interpreted as intimidation. It also could intervene more dramatically, by initiating impeachment procedures, passing legislation limiting judges’ terms in office or redefining the jurisdiction of federal courts in certain types of cases.

Intervention by Congress, however, does not sit well with some conservatives.

“A lot of conservatives may strongly disapprove of what the courts are doing but don’t think it’s proper to punish judges for the decisions,” said John Pitney, a political scientist at Claremont McKenna College and a former Republican congressional aide. “They regard that as a breach of separation of powers.”